WATCH: Sparks Fly During Zimmerman Trial Opening Statements

The murder trial in the Trayvon Martin case opened Monday with profanity and an ill-timed knock-knock joke, followed by witness testimony describing the Miami teenager’s last hours before he was fatally wounded by 29-year-old neighborhood watch volunteer George Zimmerman. Police dispatcher Sean Noffke, who Zimmerman was talking to just before shooting Martin, testifies that he never told Zimmerman to follow Martin because of liability issues. Watch the CNN video above for courtroom highlights.

The murder trial in the Trayvon Martin case opened Monday with profanity and an ill-timed knock-knock joke, followed by witness testimony describing the Miami teenager’s last hours before he was fatally wounded by 29-year-old neighborhood watch volunteer George Zimmerman. Police dispatcher Sean Noffke, who Zimmerman was talking to just before shooting Martin, testifies that he never told Zimmerman to follow Martin because of liability issues. Watch the CNN video above for courtroom highlights.